The rider of a bicycle is capable of riding it at substantial speeds. To ride safely, however, a rider must be able to slow and stop his bicycle to prevent injury to himself and to others. There are presently only two commonly used structural systems for slowing and stopping a bicycle, friction brakes and coaster brakes. Coaster brakes are themselves a friction brake, employing friction between two surfaces in the rear axle of a chain driven two-wheeled bicycle. When the pedals of the bicycle are rotated in a forward direction the gearing applies rotational force to the wheel, but when the pedals are driven in the reverse direction, the rear wheel is locked against rotation with respect to the bicycle frame.
Coaster brakes are useable on a bicycle with a chain drive which can apply force through the chain during both forward rotation and rearward rotation. Modern bicycles, however, provide the rider with a multiplicity of gear ratios so the rider can apply his muscles with the most efficient effect. The changing of the gear ratios is accomplished by either a changing of the gearing in the axle of the bicycle, or by changing of the ratios of the diameters of the chain sprockets on the axle and on the foot crank respectively. Coaster brakes are not useable with either type of the presently available multi speed drive systems, and therefor friction brakes have been used on multi speed bicycles. Friction brakes have a caliper mounted on the frame near the outer rim of the wheel and the caliper is controlled by a lever mounted on the handlebars. When the rider actuates the lever, the calipers compress two brake pads around the rim of the wheel causing friction to slow and stop the bicycle.
There are limitations to the control available to a bicycle fitted with friction type brakes. For example, a friction brake that abruptly locks the rotation of the front wheel can flip the bicycle over and cause injury to the rider. It would be desirable, therefore, to provide a method and apparatus for slowing a bicycle without relying on friction. It would also be desirable to provide an alternative method for slowing a bicycle that could be used in conjunction with multi speed drive systems of the type currently available in bicycles.